Over the past 10 years, the median price of first grade in the city has gone up by 48 percent, adjusted for inflation, compared with a 35 percent increase at private schools nationally — and just 24 percent at an Ivy League college — according to tuition data provided by 41 New York City K-12 private schools to the National Association of Independent Schools.

Indeed, this year’s tuition at Columbia Grammar and Preparatory ($38,340 for 12th grade) and Horace Mann ($37,275 for the upper school) is higher than Harvard’s ($36,305).

Schools say they have to pay teachers more to compete with the public schools, but the main push seems to be supply and demand. There are lots of parents who’ll pay anything for a place at an elite school.